The Middle East's oil producers are bracing for continued pressure from lower oil prices, with the International Monetary Fund projecting cumulative budget deficits of $320 billion over the next five years.

Approximately half of that— or $160 billion— will be sustained by energy-rich Gulf Arab nations between 2018 and 2022. Still, it's significantly lower than the cumulative deficit of $350 billion that Saudi Arabia, the United Arab Emirates, Qatar, Kuwait, Oman and Bahrain have racked up since 2015.

A global drop in oil prices since mid-2014 has forced Mideast oil exporters to take steps to consolidate spending and find new sources of revenue, including implementing sensitive measures like introducing taxes and lifting subsidies.

The IMF says in a report released on Tuesday that progress on these efforts has been uneven.